1. Field of the Invention
This invention relates to a magnetic element and a magnetic head exploiting the magneto-resistance effect, and a magnetic adjustment method for adjusting magneto-resistance characteristics of the magnetic element.
2. Description of Related Art
The giant magneto-resistance effect (GMR) is expected to be applied to a magneto-resistance effect type magnetic head, referred to below as an MR head, of a high sensitivity. On the other hand, the MR head exploiting the GMR is desirably of a small size in keeping with improvement in the recording density of the recording medium. That is, the MR head for a high density recording medium is desirably an MR device having a small sample size and exhibiting a large MR rate.
So, a layered magnetic element exhibiting a large rate of change of magneto-resistance, referred to below as the MR rate, for a small sample size not larger than one submicron, has been proposed. This sort of the magnetic element is exemplified by an MR head of an artificial lattice structure comprised of plural different sorts of materials layered together.
The MR head of the artificial lattice structure detects signals recorded on a magnetic recording medium by exploiting changes in the electrical resistance value depending on the direction of magnetization when the current is supplied in the in-plane-direction of the layered films.
In this MR head, in detecting signals of a recording medium, the current is supplied to the MR device and changes in the electrical resistance value as a result of application of a stray magnetic field are detected. As a technique of supplying the current to the MR device, it is known that the magneto-resistance effect when the current is supplied in a direction perpendicular to the film surface CPP (current perpendicular to the plane), that is CPP-GMR, is of a larger MR rate than the magneto-resistance effect when the current is supplied in a direction parallel to the film surface CIP (current in plane)-GMR, that is CIP-GMR.
However, the MR element of the artificial lattice structure suffers a problem that the electrical resistance in the direction perpendicular to the plane is on the order of 10xe2x88x9215 xcexa9 such that changes in the electrical resistance value as a result of application of the magnetic field are so small as to render the measurement difficult.
On the other hand, the magnetic head exploiting the MR element or the MRAM (magnetic random access memory) exploiting the MR element suffers from the problem that, while characteristics of the respective MR elements are desirably in a pre-set range, the production yield is lowered if the MR element lying outside the pre-set range is used.
It is therefore an object of the present invention to provide a magnetic element having an improved MR rate, a magnetic head having this MR element, and a magnetic adjustment method for improving the production yield of the magnetic head or the MRAM having an MR element.
In one aspect, the present invention provides a magnetic element which is made up of a plurality of films of different compositions, layered together, and which exhibits a magneto-resistance effect of the electrical resistance value being changed on application of a magnetic field thereto, wherein the magnetic element includes a recess for conducting the current along a layering direction of the layered films.
In this magnetic element, in which the current flows through the portion of the magnetic element not having the recess so as to have a component along the film layering direction, with the result that electrons taking part in current conduction may be propagated as the electrons traverse the boundary surfaces of the plural layered films.
In another aspect, the present invention provides a magnetic element which is made up of a plurality of films of different compositions layered together, and which exhibits a magneto-resistance effect of the electrical resistance value being changed on application of a magnetic field thereto, wherein the magnetic element includes a recess for conducting the current along a layering direction of said layered films, and wherein a projection neighboring to said recess is made up of a plurality of layered films of different compositions.
In this magnetic element, in which the current flows through the portion of the magnetic element not having the recess so as to have a component along the film layering direction, with the result that electrons taking part in current conduction may be propagated as the electrons traverse the boundary surfaces of the plural layered films.
In yet another aspect, the present invention provides a magnetic element which is made up of a plurality of films of different compositions layered together, and which exhibits a magneto-resistance effect of the electrical resistance value being changed on application of a magnetic field thereto, wherein the magnetic element includes a recess for conducting the current along a layering direction of said layered films, and wherein a projection neighboring to said recess is made up of a plurality of layered films of a unitary composition.
In this magnetic element, in which the current flows through the portion of the magnetic element not having the recess so as to have a component along the film layering direction, with the result that electrons taking part in current conduction may be propagated as the electrons traverse the boundary surfaces of the plural layered films.
In yet another aspect, the present invention provides a magnetic head including a magneto-resistance element having a magneto-resistance effect of the electrical resistance value being changed as a result of application of a stray magnetic field from a magnetic recording medium, the magneto-resistance element being made up of a plurality of layered films of different compositions and having a recess for transmitting the current along the layering direction of the layered films, and paired electrodes formed at both end faces of the magneto-resistance element perpendicular to the layering direction.
In this magnetic head, in which the current flows through the portion of the magnetic element not having the recess so as to have a component along the film layering direction, with the result that electrons taking part in current conduction may be propagated as the electrons traverse the boundary surfaces of the plural layered films.
In yet another aspect, the present invention provides a magnetic head comprising a magneto-resistance element having a magneto-resistance effect of the electrical resistance value being changed as a result of application of a stray magnetic field from a magnetic recording medium, said magneto-resistance element being made up of a plurality of layered films of different compositions and having a recess for transmitting the current along the layering direction of said layered films, and paired electrodes formed at both end faces of the magneto-resistance element perpendicular to said layering direction, wherein a projection neighboring to said recess is made up of a plurality of layered films of different compositions.
In this magnetic head, in which the current flows through the portion of the magnetic element not having the recess so as to have a component along the film layering direction, with the result that electrons taking part in current conduction may be propagated as the electrons traverse the boundary surfaces of the plural layered films.
In yet another aspect, the present invention provides a magnetic head comprising a magneto-resistance element having a magneto-resistance effect of the electrical resistance value being changed as a result of application of a stray magnetic field from a magnetic recording medium, said magneto-resistance element being made up of a plurality of layered films of different compositions and having a recess for transmitting the current along the layering direction of said layered films, and paired electrodes formed at both end faces of the magneto-resistance element perpendicular to said layering direction, wherein a projection neighboring to said recess is made up of a plurality of layered films of a unitary composition.
In yet another aspect, the present invention provides a magnetic adjustment method including preparing an electronic device including a magnetic element which is made up of a plurality of films of different compositions, layered together, and which exhibits a magneto-resistance effect of the electrical resistance value being changed on application of a magnetic field thereto, and forming a recess for conducting the current along the layering direction of the layered films to provide for a desired degree of the magneto-resistance value.
In this magnetic adjustment method, in which the current flows through the portion of the magnetic element not having the recess, to adjust the magnitude of the component perpendicular to the layering direction to adjust the degree of the magneto-resistance effect of the magnetic element.
In yet another aspect, the present invention provides a magnetic adjustment method comprising preparing an electronic device including a magnetic element which is made up of a plurality of films of different compositions, layered together, and which exhibits a magneto-resistance effect of the electrical resistance value being changed on application of a magnetic field thereto, and forming a recess for conducting the current along the layering direction of said layered films to provide for a desired degree of the magneto-resistance value, a projection neighboring to said recess being formed by a plurality of layered films of different compositions.
In this magnetic adjustment method, in which the current flows through the portion of the magnetic element not having the recess, to adjust the magnitude of the component perpendicular to the layering direction to adjust the degree of the magneto-resistance effect of the magnetic element.
In yet another aspect, the present invention provides a magnetic adjustment method comprising preparing an electronic device including a magnetic element which is made up of a plurality of films of different compositions, layered together, and which exhibits a magneto-resistance effect of the electrical resistance value being changed on application of a magnetic field thereto, and forming a recess for conducting the current along the layering direction of said layered films to provide for a desired degree of the magneto-resistance value, a projection neighboring to said recess being formed by a plurality of layered films of a unitary composition.
In this magnetic adjustment method, in which the current flows through the portion of the magnetic element not having the recess, to adjust the magnitude of the component perpendicular to the layering direction to adjust the degree of the magneto-resistance effect of the magnetic element.
In the magnetic element according to the present invention, in which there is formed a recess for conducting the current in the layering direction of the layered films, it is possible to transmit conduction electrons having a component perpendicular to the film layering direction to increase the magneto-resistance effect.
In the magnetic head according to the present invention, in which there is formed a recess for conducting the current in the layering direction of the layered films, it is possible to transmit conduction electrons having a component perpendicular to the film layering direction to increase the magneto-resistance effect to improve the S/N ratio of detected signals.
In the magnetic adjustment method according to the present invention, in which the degree of the magneto-resistance effect may be adjusted by the recess formed in the magnetic element, it is possible to improve the production yield of the magnetic head or the MRAM having the magnetic element.